NEW YORK, July 17 (Reuters) - U.S. stocks ended modestly
higher on Wednesday after Federal Reserve Chairman Ben Bernanke
said the timeline for winding down the U.S. central bank's
stimulus program was not set in stone.

Shares of Bank of America and Yahoo rose
after both companies reported stronger-than-expected quarterly
results. Both ranked among the names giving the biggest boost to
the S&P 500.

The three major U.S. stock indexes bounced back from
Tuesday's lower close, which broke the S&P 500's eight-day
string of gains.

Bernanke said the U.S. central bank still expects to start
scaling back its massive bond-buying program later this year,
but he said the timeline depended on the economic outlook.
He made the comments on Wednesday before the
House Financial Services Committee as part of his twice-yearly
report to Congress on monetary policy. On Thursday, he will
appear before the Senate Banking Committee.

"He's still being quite vague in describing exactly what to
expect next, and I think that serves his purposes. He's trying
to minimize the impact of policy change on the markets," said
Lawrence Creatura, portfolio manager at Federated Investors in
Rochester, New York.

Bernanke's comments on May 22 triggered a drop of nearly 6
percent in the S&P 500 in the month that followed. But remarks
from Bernanke and other Fed officials since then have calmed the
market and erased those declines. The S&P 500 is just several
points away from the all-time intraday high of 1,687.18 it
reached on May 22. For the year, the S&P 500 is up 17.9 percent.

Yahoo shares shot up 10.3 percent to close at $29.66, its
highest since May 2008. While Yahoo's results were mostly
lackluster, news of its stake in the fast-growing Chinese
e-commerce firm Alibaba and its product development
efforts lifted the stock. Yahoo hit an intraday high at
$29.73.

The Dow Jones industrial average rose 18.67 points,
or 0.12 percent, to end at 15,470.52. The Standard & Poor's 500
Index gained 4.65 points, or 0.28 percent, to finish at
1,680.91. The Nasdaq Composite Index advanced 11.50
points, or 0.32 percent, to close at 3,610.00.

Shares of DuPont jumped 5.3 percent to $57.25 after
Trian Fund Management's Nelson Peltz said he has amassed a "big
stake" in the chemicals maker. The stock was the Dow's top
percentage gainer.

On the flip side, shares of American Express fell 1.9
percent to $76.80 after the European Commission said it would
propose limits on fees that banks can charge to process
debit-card and credit-card transactions. After
the bell, its shares slid 0.9 percent to $76.10 after it
reported results. During the regular session, American Express
was the Dow's biggest percentage decliner.

Part of the day's upbeat tone came from the Federal
Reserve's Beige Book, which said the U.S. economy continued to
grow at a modest to moderate pace in June and early July, with
manufacturing expanding in most areas of the country.

Volume was roughly 5.7 billion shares traded on the New York
Stock Exchange, the Nasdaq and the NYSE MKT, below the average
daily closing volume of about 6.4 billion this year. On Monday,
volume hit its lowest for any full trading day this year.

In Wednesday's session, advancers outpaced decliners on the
NYSE by a ratio of nearly 2 to 1. On the Nasdaq, three stocks
rose for every two that fell.